Records added since specific month this year in SQL - mysql

Question

I have a table which contains the following data
userId | name | from
1 | aaa | 2020-09-23
2 | bbb | 2020-09-01
3 | ccc | 2019-05-12
4 | ddd | 2019-06-01
5 | eee | 2018-06-23
6 | fff | 2018-07-23
It is for an educational purpose and therefore the year runs from September to August rather than January to December. How do I output all of the users who were added since the previous September (so if it's October 2020 then 1 month ago, if it's January 2021 then 4 months ago)? The query has to be relative so that it always outputs the previous September to the time that the query is run rather than a specific September.
The result of the query should be
bbb 2020-09-01
aaa 2020-09-23

Answer 1

With NOT EXISTS:
select t.* from tablename t
where t.`from` >= concat(year(current_date), '-09-01')
and not exists (
select 1 from tablename
where name = t.name
and `from` between
concat(year(current_date), '-09-01') - interval 1 year
and
concat(year(current_date), '-09-01') - interval 1 day
)
Or maybe:
select t.* from tablename t
where t.`from` >= concat(year(current_date) - (month(current_date) < 9), '-09-01')
and not exists (
select 1 from tablename
where name = t.name
and `from` between
concat(year(current_date) - (month(current_date) < 9), '-09-01') - interval 1 year
and
concat(year(current_date) - (month(current_date) < 9), '-09-01') - interval 1 day
)
so if you execute the query in say March 2021, you will get the correct results that compare the current educational year with the previous one.
See the demo.
Results:
> userId | name | from
> -----: | :--- | :---------
> 1 | aaa | 2020-09-23
> 2 | bbb | 2020-09-01

Answer 2

You can subtract 9 months and compare to the year:
where year(`from` - interval 9 month) = year(curdate() - interval 9 month)
Actually, you might want year(curdate()) +/- 1 depending on how you are identifying the year.